Population Biology Commons^™

Modeling The Population Dynamics Of Gulf Coast Sandhill Cranes, Douglas H. Johnson, William L. Kendall

Proceedings of the North American Crane Workshop

The Mid-continent Population of sandhill cranes (Grus canadensis) has a large geographic range. contains nearly 500,000 birds, and is hunted in much of its range. The population includes 3 subspecies; the numbers of 2 of these are uncertain, and they should be afforded protection from hunting that would be detrimental to their population. The 2 subspecies of concern tend to concentrate in the eastern part of the Great Plains during fall and spring and to winter along the Gulf Coast in Texas. This paper uses the limited information availahle ahout the Gulf Coast subpopulation in a model. We …

Subspecies Composition Of Sandhill Crane Harvest In North Dakota, 1968–94, William L. Kendall, Douglas H. Johnson, Stanley C. Kohn

Proceedings of the North American Crane Workshop

North Dakota is a major fall staging area for the Mid-continent Population (MCP) of sandhill cranes (Grus canadensis), which is composed of 3 subspecies: the greater (G. c. tabida), Canadian (G. c. rawani), and lesser (G. c. canadensis). The number of cranes killed by hunters in North Dakota averaged 6,793 during the 1990-94 seasons, ranking second highest among crane-hunting states. The distribution of harvest among subspecies is important, due to concerns about the poorly known status of these subspecies, especially the greater. We estimated subspecies composition of the harvest in North Dakota by …

Nesting Success And Production Of Greater Sandhill Cranes During Experimental Predator Control At Malheur National Wildlife Refuge, Oregon,1982–83, Carroll D. Littlefield, John E. Cornely

Proceedings of the North American Crane Workshop

Greater sancfrtill cranes (Grus canadensis tabida) nest commonly on Malheur National Wildlife Refuge, Oregon, but depredations by common ravens (Corvus corax) and coyotes (Canis latrans) contributed substantially to low recruitment during the 1970's. An experimental predator removal study was initiated in 1982 to determine if nesting success and recruitment would increase if predator populations were reduced. We monitored 120 crane nests located in 2 treatment areas (ravens and coyotes removed, and only ravens removed) and 1 control area (40 nests per area). Nesting success between the 2 predator control areas differed significantly during the …

Sandhill Crane Use Of The Mid-Pecos Valley Of Eastern New Mexico, James B. Montgomery Jr.

Proceedings of the North American Crane Workshop

Sandhill cranes (Grus canadensis) were monitored during winters 1989-94 in the mid-Pecos River Valley of eastern New Mexico to detennine how many used this region following a population decline in the 1980's. Numbers annually increased to a late October/early November peak (X = 7,017), fluctuated around 6,000 through December, declined in January (X = 3,531), and again peaked in February/early March (X = 5,737). Annual crane use-days (weekly counts X 7) varied from 500,545 to 1,007,673 (X = 760,606). Cranes foraged mainly in corn and sorghum stubble and alfalfa fields. Crop averages (ha) during 1990-92 were alfalfa 21,449, …

An Experimental Release Of Whooping Cranes In Florida: The First Three Years, Stephen A. Nesbitt, Martin J. Folk, Marilyn G. Spalding, James A. Schmidt, Stephen T. Schwikert, Jane M. Nicolich, Marianne Wellington, James C. Lewis, Tom H. Logan

Proceedings of the North American Crane Workshop

Fifty-two juvenile whooping cranes (Grus americana) were soft-released in Florida from February 1993 to April 1995. The birds were released in groups ranging in size from 5 to 14 individuals. The first-year survival rate was 0.42 for all years combined. First-year rates for each year were 0.36 for 1993, 0.32 for 1994, and 0.47 for 1995. Most mortality (62%) occurred during the first 3 months following release. The survival rate of 0.81 the second year after release was similar to that of Florida sandhill cranes (G. canadensis pratensis) (0.87). Predation by bobcats (Lynx rufus) …

Causes Of Mississippi Sandhill Crane Mortality In Captivity, 1984–95, Glenn H. Olsen, George F. Gee

Proceedings of the North American Crane Workshop

During 1984-95, 111 deaths were documented in the captive flock of Mississippi sandhill cranes (Grus canadensis pulla) housed at the Patuxent Wildlife Research Center. Trauma was the leading cause of death (37%), followed by infectious/parasitic diseases (25%), anatomic abnormalities (15%), and miscellaneous (8%). No positive diagnosis of cause of death was found in 19% of the necropsies. Chicks < 2 months old suffered 76 % of captive deaths. Trauma, the greatest cause of deaths of captive juveniles and adults, is likely limited to collisions in the wild. Infectious/parasitic diseases and anatomic abnormalities could affect wild chick survival at similar rates to those of captive chicks.

Whooping Crane Mortality At Patuxent Wildlife Research Center, 1982–95, Glenn H. Olsen, Joanna A. Taylor, George F. Gee

Proceedings of the North American Crane Workshop

Whooping cranes (Grus americana) have been reared at Patuxent Wildlife Research Center since 1966. During 1982-95 there were 103 mortalities caused by infectious and parasitic diseases (46%), trauma (21 %), anatomic abnormalities (17%), miscellaneous conditions (12 %) I and open or no diagnoses (5 %). The implications that disease may have on new whooping crane flocks in Florida and Canada are discussed, based on these mortality factors in captivity.

Summary Of Sandhill Crane Hunting Seasons In North Dakota, 1968–94, David E. Sharp, John E. Cornely

Proceedings of the North American Crane Workshop

The migratory Mid-continent Population (MCP), containing 3 subspecies, is the most numerous of all sandhill crane (Grus canadensis) populations. During fall the MCP uses major staging areas in the Canadian prairie provinces and northcentral United States. In North Dakota, sport hunting of the MCP resumed in 1968, after being closed during 1916-67. The resumption and expansion of crane hunting in North Dakota during 1968-94 followed a gradual panern of implementation. Subspecies considerations, the presence of whooping cranes (G. americana), crop depredation complaints. and public reaction influenced the geographic and temporal expansion of seasons. Harvests gradually increased …

Avian Tuberculosis In A Whooping Crane: Treatment And Outcome, S. Bret Snyder, Michael J. Richard, Carol U. Meteyer

Proceedings of the North American Crane Workshop

A whooping crane (Grus americana) confirmed as suffering from Mycobacterium avium infection was treated for 1 year with daily doses of rifampin (45 mg/kg) and ethambutol (30 mg/kg) and 2 doses of M. vaccae antigen. Remission of disease occurred during therapy; however, recrudescence to active infection was suspected by 10 months after the antitubercular drugs were discontinued when the crane exhibited weight loss and had thickening of bowel wall as seen on radiographs. A second therapeutic regimen using azithromycin was then initiated (40 mg/kg fed daily) and was accompanied by a second remission within 6 weeks. After 16 …

Metal Consumption By Whooping Cranes And Possible Zinc Toxicosis, Marilyn G. Spalding, Stephen A. Nesbitt, Martin J. Folk, Lee R. Mcdowell, Maria S. Sepulveda

Proceedings of the North American Crane Workshop

Fourteen captive-reared whooping cranes (Grus americana) were transferred to a pen for soft-release in Florida. Nine were killed by predators within 6 months. We found metal objects in the stomachs of 6 of these 9 either by radiography or at necropsy. All 6 had elevated serum zinc (Zn) concentrations (x = 10.3 ± 2.7 flg/ml, range 7.2-14 .ug/ml) when compared to 3 without metal in their stomachs (X = 2.4 ± 0.92 flg/ml, range 1.6-3.4 J1.g/ml). We observed lethargy, abnormal posture, anemia, and elevated white blood cell counts in 2 cranes at or near the time of elevated …

Pair Formation By Color-Marked Whooping Cranes On The Wintering Grounds, Thomas V. Stehn

Proceedings of the North American Crane Workshop

Observations were made of color-marked whooping cranes (Grus americana) at Aransas during the 1977-94 winters. Suhadult cranes wintered near their juvenile home ranges in flocks averaging 3.12 birds. One and 2 winters prior to nesting, subadults at Aransas tended to form duos apart from other subadults. Frequencies of association 1 year prior to nesting averaged 65.4%. However, 27.7 % of pair bonds (n = 18) formed during spring migration or on the breeding grounds without any observed prior association at Aransas. Sixty-eight banded cranes formed pairs. Pair members averaged 1.06 years difference in age. Winter territories of adults …

Food And Energy Intake Rates Of Wintering Whooping Cranes Foraging On Two Selected Food Items, Felipe Chavez-Ramirez, Jay T. Nelson, R. Douglas Slack

Proceedings of the North American Crane Workshop

Number, mass, and potential energy of food items consumed by wintering whooping cranes (Grus americana) foraging on blue crab (Callinectes sapidus) and woltberry (Lycium carolinianum) fruit were estimated and compared between 2 consecutive winter periods. Mass consumed was determined through field observations by quantifying the number of items taken per unit time and the average, or modal, weight of each food item determined from collections. Gross energy intake was determined by calculating the product of mass consumed times gross energy (kJ/g) of each food item. Potential energy retained was calculated by determining metabolizable energy …

Semen Collection And Fertility In Naturally Fertile Sandhill Cranes, Guojun Chen, George F. Gee, Jane M. Nicolich, Joanna A. Taylor

Proceedings of the North American Crane Workshop

Aviculturists often ask if semen collection will interfere with fertility in naturally fertile pairs of cranes. We used 12 naturally fertile Florida sandhill crane (Grus canadensis pratensis) pairs for this study, 6 control and 6 experimental. All pairs had produced fertile eggs in previous years and were in out-of-doors pens scattered throughout different pen complexes, within auditory range but physically isolated. Semen was collected on Tuesday mornings and Friday afternoons from 26 February 1993 to 4 June 1993. We used standard artificial insemination methods to collect and to evaluate the semen and spermatozoa. Semen collection did not affect semen quality …

Results Of Eight Years Of Predator Control To Enhance Sandhill Crane Production On Malheur National Wildlife Refuge, Oregon, Gary L. Ivey

Proceedings of the North American Crane Workshop

Because of a 21 % decline in breeding pairs of greater sandhill cranes (Grus canadensis tabida) on Malheur National Wildlife Refuge from 1971 to 1985, a predator control program was initiated in 1986 to enhance production. The primary cause for the decline was low recruitment of young due to high predation by ravens (Corvus corax). raccoons (Procyon lotor), and coyotes (Canis latrans), On average, predators destroyed 46% of all crane nests and 90% of the prefledged colts. Mink (Mustela vison) were added to the program in 1993 after a study …

Long Bone Fracture Management In A Sandhill Crane: A Case Report, Patrice N. Klein, Dorothy Thompson

Proceedings of the North American Crane Workshop

A 65-day-old, juvenile Mississippi sandhill crane (Grus canadensis pulla) sustained an oblique fracture of the right middiaphyseal femur. Internal fixation by use of an intramedullary pin and full cerclage wire was performed to stabilize the fracture site. Post-operative medical management of these fractures is often unsuccessful due to secondary complications associated with long-term restraint. This report describes the successful recovery of an endangered sandhill crane with a long bone fracture of the pelvic limb through a program of incremental physical therapy beginning 2 weeks post-femoral fracture repair. Sling support, assisted walking, and hydrotherapy were methods effective in preventing …

Resolutions Passed By The North American Crane Working Group

Proceedings of the North American Crane Workshop

RECOGNITION OF THE CONTRIBUTIONS OF TOM TACHA TO CRANE RESEARCH

Participants of the Seventh North American Crane Workshop wish to recognize Tom Tacha's many contributions to the understanding of Mid-continent sandhill crane behavior, ecology, and taxonomy. Tom published 30 papers on cranes between 1979 and 1995 and was chief editor of Migratory Shore and Upland Game Bird Management in North America, published shortly before his death. Tom's Ph.D. work and other morphological and behavioral studies strongly influenced our notions of the boundaries among, and validity of. the 3 migratory sandhill crane subspecies. He set new standards for quantitative analysis of …

Status, Production And Migration Of Greater Sandhill Cranes On Agassiz National Wildlife Refuge, Minnesota, Jon J. Dimatteo

Proceedings of the North American Crane Workshop

Greater sandhill cranes (Grus canadensis tabida) nesting at Agassiz National Wildlife Refuge (NWR) in northwestern Minnesota were studied from 20 April 1984 to 10 December 1985. Local birds were monitored to determine population size and age structure, reproductive success, and migration routes and wintering grounds. Forty-two pairs were identified. Thirty-four were breeding pairs and 3 were subadult (nonbreeding) pairs. Twenty nests were found; pairs at 13 of these hatched at least 1 young. Forty-three pairs hatched a minimum of 62 young, and 28 pairs fledged 42 of 47 young. Fifteen birds were colormarked, 8 of which were radio-tagged …

An Evaluation Of Three Areas For Potential Populations Of Whooping Cranes, Janet L. Mcmillen, Stephen A. Nesbitt, Mary A. Bishop, Alan J. Bennett, Laurel A. Bennett

Proceedings of the North American Crane Workshop

Sandhill crane (Grus canadensis) populations were evaluated on the Seney NWR, Michigan, the Okefenokee Swamp, Georgia, and in southcentral Florida to evaluate their suitability to support introduced whooping cranes (G. americana). This paper compares data collected at these sites and additional data collected in northcentral Florida. The length of the egg-laying period varied from 4.5 months in central Florida to 1 month at Seney, but egg-laying ceased at all sites from mid-May to early June. Mean clutch sizes were similar 0.7-1.9). Renesting ranged from 79% in northcentral Florida to <=5% at Seney. These dates and values are consistent with nesting successes that ranged from 48% in northcentral Florida to 80% at Seney. Average annual recruitment, 12.3 juveniles/lOa adults, was highest on the Kissimmee Prairie in southcentral Florida. Average annual horne range size for the non-migratory populations were 1 km2 on the Okefenokee and 6.6 km2 on the Kissimmee. Nesting season horne range sizes ranged from 0.5 km2 on the Okefenokee to 1.8 km2 at Seney. All candidate populations successfully satisfied most of the guidelines for potential whooping crane populations as established by the Whooping Crane Recovery Team. Once reintroduction techniques have been refined, any or all of the study sites have the capacity to accommodate a flock of whooping cranes commensurate with Whooping Crane Recovery Team recommendations.

A Microcomputer Data Base For Managing Whooping Crane Observation Records, Duane A. Asherin, David B. Hamilton, Wendy M. Brown, Roderick C. Drewien

Proceedings of the North American Crane Workshop

A database called WHOOPER contains whooping crane (Grus americana) observations for the Rocky Mountain foster-parent population and currently consists of 1,438 observations covering the period 1975-1987. The dBase III Plus database management system for microcomputers is used for the application. This description of the data base and its capabilities updates the prototype database described in the 1985 Crane Workshop.

Unobstructed Visibility At Whooping Crane Roost Sites On The Platte River, Nebraska, Craig A. Faanes

Proceedings of the North American Crane Workshop

Unobstructed visibility is an important component of whooping crane (Grus americana) roosting habitat. Recent habitat modeling efforts suggest that unobstructed horizontal visibility is suitable at a minimum of 335 m. Unobstructed upstream and downstream visibility is also an important part of whooping crane roosting habitat, but quantification of that parameter has not been reported previously, or incorporated into species models. Data from the Platte River suggest that a minimum of 732 m of unobstructed upstream and downstream visibility is needed at whooping crane roost sites.

Crane Propagation At Miami Metro Zoo, 1983–1987, Carol G. Hesch

Proceedings of the North American Crane Workshop

Five species of cranes are bred at Miami Metrozoo. Few health problems have been encountered in raising a large number of chicks. Rearing cranes in close confinement, with limited resources, requires sound management and careful observation.

Sandhill Crane Surveys In The Northern Interior Highlands Of Mexico, Roderick C. Drewien, Wendy M. Brown, Elwood G. Bizeau

Proceedings of the North American Crane Workshop

Most sandhill cranes (Grus canadensis) wintering in Mexico are found in the northern Interior Highlands of Chihuahua. We surveyed sandhill cranes in the states of Chihuahua and occasionally Durango, Mexico, in winters 1972-90. The population averaged 23,106 (SD = 10,369) in 11 counts at 5-6 areas in Chihuahua. Laguna de Babicora, the most important wetland for cranes wintering in Mexico, had the largest numbers (X = 16,012), followed by Ascension (x = 2,405) and Laguna de los Mexicanos (x = 1,468). All 3 migratory subspecies were present. The lesser subspecies (G. c. canadensis) comprised 85.7% of …

Preliminary Identification Of Whooping Crane Staging Areas In Prairie Canada, Brian W. Johns

Proceedings of the North American Crane Workshop

For 60 years a passive program has been in effect to monitor the migration of whooping cranes (Grus americana) through Saskatchewan, and currently the Canadian Wildlife Service coordinates a triprovincial reporting network and operates a telephone Hot Line to receive reports of sightings of migrating cranes. Analyses of historical data reported through those efforts have identified the chronology of migration, the migration corridor through Canada, and major staging/ stopover areas in Saskatchewan. Investigations are continuing to identify specific roost sites, feeding areas and the availability of suitable habitat within the staging/ stopover area.

Isolation-Rearing Of Siberian Crane Chicks At The International Crane Foundation, Meenakshi Nagendran, Robert H. Horwich

Proceedings of the North American Crane Workshop

Three Siberian crane (Grus leucogeranus) chicks hatched in the summer of 1987 at the International Crane Foundation (lCF); Baraboo, Wisconsin, were raised in near-complete isolation from humans. The chicks were exposed to species-specific models, vocalizations, a costumed "parent" and a role-model adult Siberian crane housed in an adjacent pen. Attachment to costumed "parent," interchick interaction, and reactions to humans were measured and compared with those aspects of sandhill crane behavior under similar rearing conditions.

Re-Pairing Of Whooping Cranes At Aransas National Wildlife Refuge, Thomas V. Stehn

Proceedings of the North American Crane Workshop

Adult whooping cranes (Grus americana) on the winter range at Aransas NWR without mates may re-pair over a period of several months, while others remain un-paired throughout the winter. However, 1 association formed during the winter did not result in a pair bond.

Habitat Use By Florida Sandhill Cranes On The Kissimmee Prairie In Central Florida, Mary Anne Bishop

Proceedings of the North American Crane Workshop

Radio-tagged Florida sandhill cranes (Grus canadensis pratensis) were monitored for habitat use during 1985 and 1986 on the Kissimmee Prairie in central Florida. For both breeding and nonbreeding cranes, 93 % of the daytime locations were in 3 habitat types: cropland and plowed pasture, improved pasture, and palustrine emergent wetlands. Improved pasture was the most frequently used daytime habitat for both social classes. Radio locations were divided among 4 time blocks (3 diurnal, 1 nocturnal) and 4 3-month seasons. Time-of-day effects for use of wetlands and improved pasture were only marginally significant (1' < 0.08 and l' < 0.09, respectively) for breeders and not significant (1' < 0.30 and l' < 0.43, respectively) for nonbreeders. There was no significant difference in habitat use by breeders among seasons. Chi-square analyses of diurnal locations indicated that 4 of the 6 breeding cranes monitored used palustrine emergent wetlands more than their availability. The selection for wetlands reflects not only the rich food sources available, but also their use as midday loafing and drinking sites and as a source of cover that the upland habitats do not offer.

Cranes And Power Lines: An Analysis Of The Issue, Craig A. Faanes, Douglas H. Johnson

Proceedings of the North American Crane Workshop

As part of a 1980-82 study, the flight behavior and mortality of sandhill cranes (Grus canadensis) was studied at 4 alkaline lake sites in central North Dakota. We analyzed the behavioral response of sandhill cranes in flight at powerline sites and examined factors associated with collisions with a power line structure. Several methods that can be used to reduce crane mortality at power line sites are discussed. Findings of several other research efforts that address crane mortality at power lines are summarized.

Population Status, Hunting Regulations, Hunting Activity, And Harvests Of Mid-Continent Sandhill Cranes, David E. Sharp, William D. Vogel

Proceedings of the North American Crane Workshop

The mid·continent population of sandhill cranes (Grus canadensis) was protected from 1916 until 1961, when hunting resumed on a limited basis. Areas open to hunting were experimentally expanded during 1961-72, but during the subsequent 1975-90 period only minor changes were made in the 8 Central Flyway states that established hunting seasons. Annual spring surveys conducted during 1982-90 indicated the population was stable at objective levels, with spring populations estimated at about 540,000 and fall flights near 590,000. Special federal hunting permits have been required for all bunters participating in regular seasons in the Central Flyway since 1975, where …

Contaminants In Habitat, Tissues, And Eggs Of Whooping Cranes, James C. Lewis, Roderick C. Drewien, Ernie Kuyt, Charles Sanchez Jr.

Proceedings of the North American Crane Workshop

Sampling of contaminants in the principal habitat areas of whooping cranes (Grus americana) of both the Rocky Mountain and the Aransas/Wood Buffalo National Park whooping crane populations began in the mid-1980's. Contaminants in eggs and tissues of whooping cranes were sampled opportunistically since the 1960's. Chlorinated hydrocarbons existed in low levels in the environment. Some trace elements including aluminum, arsenic, cadmium, chromium, copper. mercury, selenium, and zinc are of sufficient abundance to justify continued monitoring. Declines over time in residues of DDT and mercury in tissues and eggs reflected the prohibition in use of these as pesticides or …

Progress In Satellite Tracking Cranes, David H. Ellis, Dwight G. Smith, Glenn H. Olsen, Mark R. Fuller, Steven E. Landfried, Hiroyoshi Higuchi, Charles H. Vermillion

Proceedings of the North American Crane Workshop

We review the history of tracking cranes with satellite telemetry and identify some of the difficulties in designing satellite transmitters and harnesses for cranes. Miniaturization of these transmitters and a plethora of harnessing experiments since 1989 allow us to recommend limited application of this technology to all species of cranes. We are still uncertain, however, if cranes harnessed with satellite telemetry devices are able to reproduce after migration. Because of this uncertainty, we urge caution in the use of this technology, especially with breeding adults in severely endangered popUlations. This manuscript also describes continuing research needs.